Research Engineer, Post-Training

What You'll Do

• Drive post-training experiments, pushing agent performance while navigating the Pareto frontier of cost, latency, security, and governance.
• Optimize agent harnesses, including domain-specific skills, tools, subagents, retrieval strategies, and validation loops that improve quality on long-horizon legal work.
• Design and develop grading and reward systems that are reliable enough for evaluation, efficient enough for iteration, and strict enough for high-stakes legal work.
• Study agent behavior, identifying patterns that correlate with successful work product, and converting those findings into training data, evals, or harness changes.
• Work with Harvey researchers and external research partners to define experiments, evaluate methodology, review results, and keep projects moving toward concrete model improvements.

What You Have

• Hands-on experience with post-training or model-training work, such as SFT, preference optimization, RLHF/RLAIF, reward modeling, distillation, or adapting open-weight models to specialized domains.
• Strong judgment about model behavior: you can read traces, inspect outputs, identify failure modes, and reason about whether a metric is measuring the thing that matters.
• Strong Python and research-engineering ability. You can write clean code, debug experiments, and build the simple but reliable systems needed to make research move faster.
• Ability to self-manage ambiguous applied research projects and communicate clearly with researchers, engineers, product teams, domain experts, and external partners.

Nice to Have

• Experience building data or evaluation infrastructure for ML workflows, such as dataset curation pipelines, model-output processing, experiment tracking, evaluation dashboards, or regression analysis tooling.
• Experience with distributed training, inference systems, GPU workloads, or large-scale ML experimentation.
• Research publications, open-source contributions, or shipped industry work in LLMs, agents, evaluation, or ML systems.